Low insulin means high blood sugar (high blood glucose, or hyperglycemia) which can leave you achy, tired and weak in the short term, and can lead to infections, nerve damage (diabetic neuropathy) and loss of vision (diabetic retinopathy) in the longer term. In extreme cases, high blood sugar can be fatal. Major organs, like your heart, brain and kidneys, and your whole nervous system can shut down from a lack of sugar supply.
